Oh: Brief Walks, and Chocolate Eaters

July 24th, 2014

What of walks and chocolate eaters? Oh, maybe this:

Brisk walking reduces ad libitum snacking in regular chocolate eaters during a workplace simulation,” Hwajung Oh [pictured here], Adrian H. Taylor, Appetite, Volume 58, Issue 1, February 2012, Pages 387-392. The authors, at the  University of Exeter, UK, report their discovery:

“A brief walk may help to reduce ad libitum snacking in regular chocolate eaters.”

Banding-together of breeders: Seven sperm abreast

July 23rd, 2014

Ig Nobel Prize winner Mahadevan (2007 Ig Nobel physics prize, for studying how sheets become wrinkled) and colleagues have taken an applied-mathematical look at yet another unanswered question. As happens so often with Mahadevan and his merry, varying band of collaborators, a better-than-anyone-had-before answer appeared. Details are in this study:

The dynamics of sperm cooperation in a competitive environment,” Heidi S. Fisher, Luca Giomi, Hopi E Hoekstra, L. Mahadevan, BioRXiv, 2014. The authors, at Harvard University and the International School for Advanced Studies, Trieste, Italy, report:

“we use fine-scale imaging and a minimal mathematical model to study sperm aggregation in the rodent genus Peromyscus. We demonstrate that as the number of sperm cells in an aggregate increase, the group moves with more persistent linearity but without increasing speed; this benefit, however, is offset in larger aggregates as the geometry of the group forces sperm to swim against one another. The result is a non-monotonic relationship between aggregate size and average velocity with both a theoretically predicted and empirically observed optimum of 6-7 sperm/aggregate.”

Ed Yong, in his Not Exactly Rocket Science blog, has a nice essay about this.

Here’s further detail from the study itself:

mouse-sperm-7

BONUS (possibly not strongly related): The 1956 essay “The Magical Number Seven, Plus or Minus Two: Some Limits on our Capacity for Processing Information

BONUS (probably unrelated): “Researchers find first sign that tyrannosaurs hunted in packs

Computational gastronomy – part 2 – ‘Active Odor Cancellation’

July 23rd, 2014

The Varshney twins – Dr. Kush Varshney (currently at IBM) and Professor Lav Varshney (previously at IBM) – have authored a series of papers on the theme of computational gastronomy, one of which, on Food Steganography, we looked at recently.

Example 2. Active Odor Cancellation. (IEEE International Workshop on Statistical Signal Processing, Gold Coast, Australia, June-July 2014.)Food_odor_cancelled

“Noise cancellation is a traditional problem in statistical signal processing that has not been studied in the olfactory domain for unwanted odors. In this paper, we use the newly discovered olfactory white signal class to formulate optimal active odor cancellation using both nuclear norm-regularized multivariate regression and simultaneous sparsity or group lasso-regularized non-negative regression. As an example, we show the proposed technique on real-world data to cancel the odor of durian, katsuobushi, sauerkraut, and onion.”

Coming soon: Computational gastronomy part 3

A searchable database of Ig Nobel Prize winners

July 22nd, 2014

Our friends at Silk have put together a searchable database of Ig Nobel Prize winners.

Give it a try!

Lots of famous physicists (videos)

July 22nd, 2014

A person named William Kite has been sending us letters—lots of letters— asking that we show more pictures of what he calls “famous physics people”. For the benefit of Mr. Kite (and in truth, merely because of the historical appeal of his name), here are two videos filled with, mostly, moving pictures of famous physicists,  Erwin Schrodinger, Niels Bohr, Werner Heisenberg, Auguste Piccard, Paul Dirac, Max Born, Wolfgang Pauli, Louis de Broglie, Marie Curie, Hendrik Lorentz, Albert Einstein, Hermann Weyl, Paul Erdos (whom some purists will say was purely a mathematician) and several others:

BONUS: Wellerstein peers at the hair of physicists